The objectives of this project are to define the role of ascending intrauterine infection in the etiology of preterm labor and delivery, to elucidate the cellular and molecular mechanisms signalling preterm parturition in the setting of infection and to apply this knowledge to improve the diagnostic and therapeutic approach to preterm labor. Clinical investigation has focused on determining the frequency and clinical significance of microbial invasion of the amniotic cavity in patients with preterm labor, preterm premature rupture of membranes, cervical incompetence and normal labor at term. We have established the value and limitations of different rapid laboratory tests in the diagnosis of microbial invasion of the amniotic cavity and in the prediction of preterm delivery. Laboratory investigation has focused on the study of macrophage cytokines (interleukin-1, tumor necrosis factor, interleukin-6) on the mechanisms of human parturition associated with infection, the development of an animal model for ascending intrauterine infection and the study of the role of anticytokine agents (interleukin-I natural receptor antagonist and tumor necrosis factor antagonists) in preventing infection induced preterm delivery.